body{
    margin: 0;
    min-width: 100%;
    min-height: 20%;
}
.logo{
    float:left;
    height:43px;
    width:226px;
    background-image:url(../pic/logo.png);
}
.username{
    float:right;
    color:#999;
    line-height:45px;
    margin-right:25px;
}